For various surgical procedures, and most commonly for coronary artery bypass grafting (CABG), it is common to remove or "harvest" a vascular conduit or vessel section, such as an artery or vein, from its natural location in a patient's body and to use it elsewhere in the body. In CABG surgery, the vascular conduit is used to establish a bypass between an arterial blood source and the coronary artery being bypassed. Often an artery proximate the heart, such as one of the internal mammary arteries, can be used as the bypass conduit. Alternatively, one or more of the saphenous veins in the legs, or a radial artery in an arm, are used as the vascular conduit, and are sometimes preferred by some surgeons in emergency situations, and where multiple bypass vessels are needed. For patient's requiring multiple bypasses, a surgeon may use the saphenous vein in addition to various arteries to revascularize a patient's heart.
The conventional surgical procedure used to harvest the saphenous vein and the like for use in the CABG surgery, is generally very traumatic to a patient. The procedure involves making a continuous incision in the leg for the full length of the desired vein section in order to provide adequate exposure for visualizing the vein and for introducing surgical instruments to sever, cauterize and ligate the tissue and side branches of the vein. The incision must then be closed by suturing or stapling along its length. Many patients suffer significant complications such as skin loss, infections and impaired healing, saphenous nerve damage, hematomas and may experience lower extremity discomfort for months. The procedure also leaves disfiguring scars, increases patient recovery time and hospital stay and thus adds to the cost of the CABG procedure.
In an attempt to overcome these problems, less-invasive techniques for harvesting vessels have been developed, employing one or two small incisions, generally one at each end of the section of vessel to be removed. Blunt mechanical force is applied by introduction of several surgical instruments of successively larger diameters to first create a working space in the tissue surrounding the vein while separating the vein from the surrounding tissue. Then further multiple instruments are introduced into the generally limited working space to dissect, clip and/or cauterize side branches of the vessel to allow harvesting of the desired section of the vessel. An endoscope generally is required for such a procedure to enhance visualization of the vessel and the surrounding tissue in the rather limited working space, particularly at a distance from the incision.
Even where these less invasive techniques reduce the overall length of the incision, the trauma to the vessel, the surrounding tissue and to the patient can be severe. In particular, the harvesting procedure itself may actually be lengthened and the trauma to the vessel potentially increased due to the number of surgical instruments that are needed for the harvesting procedure, and due to the fact that the instruments are reintroduced through the incision into the limited region between the patient's skin and vein. The trauma to the vessel as well as to the patient is exacerbated by the condition that the patient's skin and associated fat globules and tissue tend to collapse about the saphenous vein. It follows that in each withdrawal and subsequent insertion of a surgical instrument into the region above the vessel may cause added irritation, damage and trauma to the vessel. A nick in the vessel or damage to a side branch of the vessel causes undesirable problems since any damage to the harvested section of vessel must be repaired before it can be used as a graft. The repairs themselves are undesirable since they can lead to subsequent failure of the graft at the point of the damage and repair.